I have water leaking under the car, from the firewall, checked inside heater core...no leak, no water comming off the engine block......can anyone give some help on this one?

Is it actual water, or coolant? If water, its probabaly the drain from the A/C. If coolant, then set a clean piece of cardboard under the car overnight and see if you can catch it dripping. If it does then you know in what area to start looking.

If coolant my vote is coolant elbow or waterpump.

it was coolant at first, as we added plain water to try and find the leak

OK I hit the area hard and repeatedly with a blunt object, but that only dented other items around it seriously!!!!!! just kidin

Have you checked all the hoses back there? I know both heater hoses run to the alt. brakcet. Maybe its leaking there. Next time you get the car up to temp, park it somewhere and shut it off and pop the hood. Take a look at ALL the hoses and the 2 coolant elbows, etc. Anything that could leak coolant.

If it is water it's just condensation.

The only think by the firewall are the 2 heater core hoses. Check those.

If not, check the coolant elbows and the alt. bracket.

Problem Found......there is a panel on the outside (engine side) of the firewall, 3 or 4 screws removes it, there I saw the Heater Core hoses.....thanks everyone!